Thanks to kristopher.roy there's finally a working AutoRateAccurate again for MM4. Basically it's the same like 2.5 for now but new features are likely to come in 3.1. We changed the version number because 3.x is for MM4 only while 2.x was for MM3. The first and most important goal is to improve speed and stability.
AutoRateAccurate
What is it?
This script rates the songs of your library based on informations like Playcounter, DaysInLibrary, PlayedPerDay, LastPlayed and SkipCounter. This way the rating will also be increased if you listened a song with your portable player like ipod!
And it is really easy to use: Normally you only have to enable AutoRateAccurate in the MediaMonkey-Options.

Features:
The script does a lot more than just rating songs:
Autocalibration
This is one of the mainfeatures of AutoRateAccurate. It calibrates automatically the rating-algorithm so that you never get too much high rated or too much low rated songs. In the options you can decide how much percent of your library should have five stars and then automatically the algorithm gets adjusted. AND: If you don't want the script to give some ratings, for example half star, just set that value to 0%.
This Autocalibration can be started automatically on startup of MediaMonkey, which is optional but recommended.
KeepManualRatings
If this feature is enabled only songs with no ratings get autorated. Songs which you already rated by hand won't get overwritten because they probably are even more accurate than the autoratings. This option is also very useful if you just want to try out AutoRateAccurate - if you don't like it just let it delete the autoratings with "Delete AutoRatings".
BaseRating
If there are not enough information (if a song never has been played for example) AutoRateAccurate is not able to calculate a rating. That's why you can set a default rating for all new songs which can't be autorated.
More to come...
Downloads:
AutoRateAccurate v3.0.0 - Installer
Complete changelog
Changelog 3.0:
-Added: MM4 support

-Changed: The script now uses the official SkipCount from MM4.
-Removed: SkipDetection as it's already implemented in MM4 by default.
-Removed: OptPlaycount to improve stability and performance.
-Fixed: Fixed filter problem with fresh setups (Thanks kristopher.roy!)
-Fixed: Regression in code removal.
Donations:
AutoRateAccurate is completely free. So don't feel obligated to pay something! I'm already pleased by "thank you"-posts in this thread.

Although you can surprise me with something from my Amazon wishlist.

But please remember that I can't promise to work on the script regularly as I my free time is really limited.
Have fun!

Big_Berny